Cancers and infections can be treated by administering reagents that modulate the immune system. These reagents include vaccines, cytokines, antibodies, and small molecules, such as CpG oligodeoxynucleotides and imidazoquinolines (see, e.g., Becker (2005) Virus Genes 30:251-266; Schetter and Vollmer (2004) Curr. Opin. Drug Devel. 7:204-210; Majewski, et al. (2005) Int. J. Dermatol. 44:14-19), Hoffmann, et al. (2005) J. Clin. Virol. 32:86-91; Huber, et al. (2005) Infection 33:25-29; Carter (2001) Nature Revs. Cancer 1:118-129; Dechant and Valaerius (2001) Crit. Revs. Oncol. 39:69-77; O'Connor, et al. (2004) Neurology 62:2038-2043). Vaccines, including classical vaccines (inactivated whole organisms, extracts, or antigens), dendritic cell (DC) vaccines, and nucleic acid-based vaccines, are all useful for treating cancers and infections (see, e.g., Robinson and Amara (2005) Nat. Med. Suppl. 11:S25-S32; Plotkin (2005) Nat. Med. Suppl. 11:S5-S11; Pashine, et al. (2005) Nat. Med. Suppl. 11:S63-S68; Larche and Wraith (2005) Nat. Med. Suppl. 11:S69-S76). Another reagent useful for modulating the immune system is Listeria monocytogenes (L. monocytogenes), and this reagent has proven to be successful in treating cancers and tumors (see, e.g., Brockstedt, et al. (2004) Proc. Natl. Acad. Sci. USA 101:13832-13837; Brockstedt, et al (2005) Nat. Med. 11:853-860); Starks, et al. (2004) J. Immunol. 173:420-427; Shen, et al. (1995) Proc. Natl. Acad. Sci. USA 92:3987-3991).
Recombinant Listeria strains have been developed as vaccines against viruses and tumors (see, e.g., Starks, et al. (2004) J. Immunol. 173:420-427; Gunn, et al. (2001) J. Immunol. 167:6471-6479; Ikonomidis, et al. (1994) J. Exp. Med. 180:2209-2218; Mata, et al. (2001) Vaccine 19:1435-1445; Mata and Paterson (1999) J. Immunol. 163:1449-1456; Mata, et al. (1998) J. Immunol. 161:2985-2993; Friedman, et al. (2000) J. Virol. 74:9987-9993; Soussi, et al. (2002) Vaccine 20:2702-2712; Saklani-Jusforgues, et al. (2003) Infect. Immun. 71:1083-1090; Soussi, et al. (2000) Infect. Immunity 68:1498-1506; Tvinnereim, et al. (2002) Infect. Immunity 70:153-162; Rayevskaya, et al. (2002) J. Virol. 76:918-922; Frankel, et al. (1995) J. Immunol. 55:4775-4782; Jensen, et al. (1997) J. Virol. 71:8467-8474; Jensen, et al. (1997) Immunol. Rev. 158:147-157; Lin, et al. (2002) Int. J. Cancer 102:629-637; Peters, et al. (2003) FEMS Immunol. Med. Microbiol. 35:243-253; Peters, et al. (2003) J. Immunol. 170:5176-5187; Paterson (2003) Immunol. Res. 27:451-462; Paterson and Johnson (2004) Expert Rev. Vaccines 3:S119-S134; Ochsenbein, et al. (1999) Proc. Natl. Acad. Sci USA 96:9293-9298; Hess, et al. (2000) Adv. Immunol. 75:1-88).
L. monocytogenes has a natural tropism for the liver and spleen and, to some extent, other tissues such as the small intestines (see, e.g., Dussurget, et al. (2004) Ann. Rev. Microbiol. 58:587-610; Gouin, et al. (2005) Curr. Opin. Microbiol. 8:35-45; Cossart (2002) Int. J. Med. Microbiol. 291:401-409; Vazquez-Boland, et al. (2001) Clin. Microbiol. Rev. 14:584-640; Schluter, et al. (1999) Immunobiol. 201:188-195). Where the bacterium resides in the intestines, passage to the bloodstream is mediated by listerial proteins, such as ActA and intemalin A (see, e.g., Manohar, et al. (2001) Infection Immunity 69:3542-3549; Lecuit, et al. (2004) Proc. Natl. Acad. Sci. USA 101:6152-6157; Lecuit and Cossart (2002) Trends Mol. Med. 8:537-542). Once the bacterium enters a host cell, the life cycle of L. monocytogenes involves escape from the phagolysosome and to the cytosol. This life cycle contrasts with that of Mycobacterium, which remains inside the phagolysosome (see, e.g., Clemens, et al. (2002) Infection Immunity 70:5800-5807; Schluter, et al. (1998) Infect. Immunity 66:5930-5938; Gutierrez, et al. (2004) Cell 119:753-766). L. monocytogenes' escape from the phagolysosome is mediated by listerial proteins, such as listeriolysin (LLO), PI-PLC, and PC-PLC (see Portnoy, et al. (2002) J. Cell Biol. 158:409-414).
Vaccines for treating cancers or infections are often ineffective because of a lack of appropriate reagents. The present invention fulfills this need by providing polynucleotides, fusion protein partners, plasmids and bacterial vaccines, useful for enhancing the expression or immune processing of antigens, and for increasing survival to cancers and infections.